Method and apparatus for dissemination of timing information in distributed synchronization device to device networks

Abstract

A method, an apparatus, and a computer program product for wireless communication are provided in connection with improving convergence to a common timing structure for devices in a distributed synchronization D2D network. In an example, a communications device is equipped to detect, by a UE, a synchronization signal during a listening slot duration scan of a communication channel. In an aspect, the listening slot duration may be defined based on a first timing structure, and the synchronization signal may be defined based on a second timing structure. The communications device may further be equipped to obtain timing information associated with the second timing structure from the synchronization signal, and determine whether the first timing structure or the second timing structure is a preferred timing structure.

What is claimed is: 
     
         1 . A method of wireless communications for a user equipment (UE) in a device-to-device (D2D) network with distributed synchronization, comprising:
 detecting, by the UE, a synchronization signal during a listening slot duration scan of a communication channel, wherein the listening slot duration is defined based on a first timing structure, and wherein the synchronization signal is defined based on a second timing structure;   obtaining timing information associated with the second timing structure from the synchronization signal; and   determining whether the first timing structure or the second timing structure is a preferred timing structure.   
     
     
         2 . The method of  claim 1 , further comprising:
 aligning with the second timing structure based upon the determination that the second timing structure is the preferred timing structure.   
     
     
         3 . The method of  claim 2 , further comprising:
 transmitting at least a portion of the obtained timing information during a synchronization channel associated with the first timing structure.   
     
     
         4 . The method of  claim 2 , further comprising:
 transmitting the at least the portion of the obtained timing information during a synchronization channel associated with any timing structure other than the preferred timing structure.   
     
     
         5 . The method of  claim 3 , wherein the synchronization channel includes a sub-channel allocated to periodically transmit timing information, and wherein an indicator associated with the at least the portion of the timing information is transmitted during the sub-channel. 
     
     
         6 . The method of  claim 3 , wherein the synchronization channel includes a sub-channel allocated for random access, and wherein an indicator associated with the at least the portion of the timing information is transmitted during the sub-channel. 
     
     
         7 . The method of  claim 6 , wherein the indicator comprises at least one of:
 an indication that congestion in periodically used transmission resources is above a threshold value; or   a class identifier of the UE.   
     
     
         8 . The method of  claim 1 , wherein the listening slot comprises a duration greater than or equal to a duration between two consecutive synchronization channel allocations in the first timing structure. 
     
     
         9 . The method of  claim 8 , wherein the listening slot comprises multiple non-contiguous subslots. 
     
     
         10 . The method of  claim 1 , wherein the listening slot is selected based on at least one of:
 a pseudo-random slot determined each slow scale period; or   information associated with an identity of the UE.   
     
     
         11 . The method of  claim 1 , wherein the timing information includes at least one of:
 an indication of a presence of the preferred timing structure;   an identifier associated with the preferred timing structure; or   an offset between a synchronization channel associated with the first timing structure and the synchronization channel associated with the preferred timing structure.   
     
     
         12 . A method of wireless communications for a user equipment (UE) in a device-to-device (D2D) network with distributed synchronization, comprising:
 detecting, by the UE, timing information received during a synchronization channel duration associated with a first timing structure, wherein the timing information is for a synchronization channel associated with a preferred timing structure, and wherein the preferred timing structure is different than the first timing structure; and   aligning UE communications timing with the preferred timing structure.   
     
     
         13 . The method of  claim 12 , wherein the aligning further comprises:
 scanning for a listening slot duration to detect a synchronization channel associated with the preferred timing structure.   
     
     
         14 . The method of  claim 12 , wherein the timing information includes an offset between a synchronization channel associated with the preferred timing structure and the synchronization channel associated with the first timing structure. 
     
     
         15 . A method of wireless communications for a user equipment (UE) in a device-to-device (D2D) network with distributed synchronization, comprising:
 determining, by the UE, a presence of a preferred timing structure, wherein the UE is currently using a first timing structure for communications, and wherein the preferred timing structure is different than the first timing structure; and   transmitting timing information associated with the preferred timing structure during a synchronization channel duration associated with the first timing structure.   
     
     
         16 . The method of  claim 15 , wherein the timing information includes a class identifier of the UE which indicates a preference level for the preferred timing structure. 
     
     
         17 . The method of  claim 15 , wherein the presence of the preferred timing structure is based on the determined based on at least one of:
 availability of a global position system (GPS) based timing value;   presence of a comparatively more precise clock value; or   an indication that the UE has access to a timing value based on a wide area network (WAN).   
     
     
         18 . An apparatus of wireless communications in a device-to-device (D2D) network with distributed synchronization, comprising:
 means for detecting, by a user equipment (UE), a synchronization signal during a listening slot duration scan of a communication channel, wherein the listening slot duration is defined based on a first timing structure, and wherein the synchronization signal is defined based on a second timing structure;   means for obtaining timing information associated with the second timing structure from the synchronization signal; and   means for determining whether the first timing structure or the second timing structure is a preferred timing structure.   
     
     
         19 . An apparatus of wireless communications in a device-to-device (D2D) network with distributed synchronization, comprising:
 means for detecting, by a user equipment (UE), timing information received during a synchronization channel duration associated with a first timing structure, wherein the timing information is for a synchronization channel associated with a preferred timing structure, and wherein the preferred timing structure is different than the first timing structure; and   means for aligning UE communications timing with the preferred timing structure.   
     
     
         20 . An apparatus of wireless communications in a device-to-device (D2D) network with distributed synchronization, comprising:
 means for determining, by a user equipment (UE), a presence of a preferred timing structure, wherein the UE is currently using a first timing structure for communications, and wherein the preferred timing structure is different than the first timing structure; and   means for transmitting timing information associated with the preferred timing structure during a synchronization channel duration associated with the first timing structure.   
     
     
         21 . A computer program product, comprising:
 a computer-readable medium comprising code for:
 detecting, by a user equipment (UE) in a device-to-device (D2D) network with distributed synchronization, a synchronization signal during a listening slot duration scan of a communication channel, wherein the listening slot duration is defined based on a first timing structure, and wherein the synchronization signal is defined based on a second timing structure; 
 obtaining timing information associated with the second timing structure from the synchronization signal; and 
 determining whether the first timing structure or the second timing structure is a preferred timing structure. 
   
     
     
         22 . A computer program product, comprising:
 a computer-readable medium comprising code for:
 detecting, by a user equipment (UE) in a device-to-device (D2D) network with distributed synchronization, timing information received during a synchronization channel duration associated with a first timing structure, wherein the timing information is for a synchronization channel associated with a preferred timing structure, and wherein the preferred timing structure is different than the first timing structure; and 
 aligning UE communications timing with the preferred timing structure. 
   
     
     
         23 . A computer program product, comprising:
 a computer-readable medium comprising code for:
 determining, by a user equipment (UE) in a device-to-device (D2D) network with distributed synchronization, a presence of a preferred timing structure, wherein the UE is currently using a first timing structure for communications, and wherein the preferred timing structure is different than the first timing structure; and 
 transmitting timing information associated with the preferred timing structure during a synchronization channel duration associated with the first timing structure. 
   
     
     
         24 . An apparatus for communication in a device-to-device (D2D) network with distributed synchronization, comprising:
 a processing system configured to:   detect, by a user equipment (UE), a synchronization signal during a listening slot duration scan of a communication channel, wherein the listening slot duration is defined based on a first timing structure, and wherein the synchronization signal is defined based on a second timing structure;   obtain timing information associated with the second timing structure from the synchronization signal; and   determine whether the first timing structure or the second timing structure is a preferred timing structure.   
     
     
         25 . The apparatus of  claim 24 , wherein the processing system is further configured to:
 align with the second timing structure based upon the determination that the second timing structure is the preferred timing structure.   
     
     
         26 . The apparatus of  claim 25 , wherein the processing system is further configured to:
 transmit at least a portion of the obtained timing information during a synchronization channel associated with the first timing structure.   
     
     
         27 . The apparatus of  claim 25 , wherein the processing system is further configured to:
 transmit the at least the portion of the obtained timing information during a synchronization channel associated with any timing structure other than the preferred timing structure.   
     
     
         28 . The apparatus of  claim 26 , wherein the synchronization channel includes a sub-channel allocated to periodically transmit timing information, and wherein an indicator associated with the at least the portion of the timing information is transmitted during the sub-channel. 
     
     
         29 . The apparatus of  claim 26 , wherein the synchronization channel includes a sub-channel allocated for random access, and wherein an indicator associated with the at least the portion of the timing information is transmitted during the sub-channel. 
     
     
         30 . The apparatus of  claim 29 , wherein the indicator comprises at least one of:
 an indication that congestion in periodically used transmission resources is above a threshold value; or   a class identifier of the UE.   
     
     
         31 . The apparatus of  claim 24 , wherein the listening slot comprises a duration greater than or equal to a duration between two consecutive synchronization channel allocations in the first timing structure. 
     
     
         32 . The apparatus of  claim 31 , wherein the listening slot comprises multiple non-contiguous subslots. 
     
     
         33 . The apparatus of  claim 24 , wherein the listening slot is selected based on at least one of:
 a pseudo-random slot determined each slow scale period; or   information associated with an identity of the UE.   
     
     
         34 . The apparatus of  claim 24 , wherein the timing information includes at least one of:
 an indication of a presence of the preferred timing structure;   an identifier associated with the preferred timing structure; or   an offset between a synchronization channel associated with the first timing structure and the synchronization channel associated with the preferred timing structure.   
     
     
         35 . An apparatus for communication in a device-to-device (D2D) network with distributed synchronization, comprising:
 a processing system configured to:   detect, by a user equipment (UE), timing information received during a synchronization channel duration associated with a first timing structure, wherein the timing information is for a synchronization channel associated with a preferred timing structure, and wherein the preferred timing structure is different than the first timing structure; and   align UE communications timing with the preferred timing structure.   
     
     
         36 . The apparatus of  claim 35 , wherein the processing system is further configured to:
 scan for a listening slot duration to detect a synchronization channel associated with the preferred timing structure.   
     
     
         37 . The apparatus of  claim 35 , wherein the timing information includes an offset between a synchronization channel associated with the preferred timing structure and the synchronization channel associated with the first timing structure. 
     
     
         38 . An apparatus for communication in a device-to-device (D2D) network with distributed synchronization, comprising:
 a processing system configured to:   determine, by a user equipment (UE), a presence of a preferred timing structure, wherein the UE is currently using a first timing structure for communications, and wherein the preferred timing structure is different than the first timing structure; and   transmit timing information associated with the preferred timing structure during a synchronization channel duration associated with the first timing structure.   
     
     
         39 . The apparatus of  claim 38 , wherein the timing information includes a class identifier of the UE which indicates a preference level for the preferred timing structure. 
     
     
         40 . The apparatus of  claim 38 , wherein the presence of the preferred timing structure is based on the determined based on at least one of:
 availability of a global position system (GPS) based timing value;   presence of a comparatively more precise clock value; or   an indication that the UE has access to a timing value based on a wide area network (WAN).